The present invention relates generally to electrical device testing, and more particularly to a two-stage device-under-test (DUT) clamp with DUT-linked double action for testing an electrical device.
Final level test of electrical devices often involves insertion probing of one or more receptacles, pressing buttons, and/or activating switches on the device. For example, a cellular phone often includes a receptacle configured as an array of signal points on the device under test (hereinafter referred to as the “system connector”), an audio receptacle into which a headset audio plug is inserted or a charger receptacle into which an A/C charger plug is inserted to charge up the device, and a numeric keypad comprising a set of buttons used for dialing. During final level test, the functionality of each of these features of the phone must be tested prior to shipping.
Accordingly, various tests are performed on the device (hereinafter referred to as “device under test” or “DUT”). Typically at least one or more tests require insertion probing of one or more of the DUT receptacles. Insertion probing involves the insertion of a probe into a mating DUT receptacle such that the probe and DUT receptacle make electrical contact. The electrical contact is the means through which the probe stimulates and/or receives measurement signals from the DUT. In addition, automated button pressing is required to test the operation of the keypad. Typical final level testing of electronic devices is performed in an automated environment, often using robotic actuators.
In order to accurately test a DUT in such an automated environment, several conditions must be met. First, accurate location of the DUT relative the testing probes is required for proper probing and button location. Second, the fixture that holds the DUT must firmly lock the DUT into position in order to ensure accurate probing/button-pressing force, to prevent cosmetic damage to the DUT, and to prevent the DUT from moving around during test resulting in electrical and RF signal loss and falsely failing tests.
In order to meet these requirements, the DUT is typically clamped into a known position relative the robotic tester.
Some prior art clamping solutions attempt to clamp the DUT against a fixture from the top of the DUT. However, oftentimes this configuration is not available as a clamping option due to risk of cosmetic damage to the DUT being clamped.
DUT clamps that clamp from below the DUT typically require the clamp walls to be parallel and opposing each other, and that the linear motion of the clamp be perpendicular to the wall planes. This configuration may not be feasible with certain DUT designs.
In addition, some prior art clamping solutions often use separate actuators for performing individual clamping motions. However, more actuators add complexity, cost, and tester space.
Finally, some prior art clamping solutions use custom-made link parts, adding complexity to the design.
Accordingly, although the idea of clamping a DUT is itself conceptually straightforward, the design of a clamping mechanism that is used for the purpose of fixing a DUT in place for insertion probing and button-pressing testing requires several important considerations. First, the DUT must be accurately located within the clamp to allow small probe points (e.g., the pins of a system connector) to be accurately probed. Second, clamping should be performed without risk of cosmetic damage to the DUT. Finally, the clamp should be designed with minimal complexity, cost, and space.